Aspirants can effectively use flashcards for UPSC preparation by incorporating active recall and spaced repetition techniques. Creating concise, focused cards that cover essential facts, concepts, or current affairs enables rapid review and retention. Using visual aids or mnemonics can enhance memory retention, making flashcards more effective. It is also beneficial to categorize flashcards by subjects or themes, allowing for organized study sessions. Regularly updating and reviewing cards can help reinforce learning and identify weaker areas. Integrating digital flashcard apps can facilitate on-the-go learning, making preparation more flexible and productive.